Male infertility commonly refers to the inability of a male to induce pregnancy in a fertile female after a period of 12 months. Male infertility represents approximately 40% of couple infertility causes. Most of male infertility cases are due to sperm abnormalities caused by a range of conditions, such as, anatomical problems, hormonal imbalances, genetic defects and idiopathic cases.
Sperm abnormalities are categorized as an abnormal sperm production with shape or motile defects, abnormal low sperm number (oligospermia) or seemingly without any sperm (azoospermia).
Treatment of male infertility depends on the underlying medical conditions that cause the fertility problem. For example, drug therapy may be used to treat hormonal disorders while surgery may be conducted in cases of obstruction in the reproductive tract. When treatment does not remedy the infertile condition, Assisted Reproductive Techniques (ARTs), such as, In Vitro Fertilization (IVF) and Intracytoplasmic Sperm Injection (ICSI), are applied. ICSI may involve obtaining semen through invasive procedures, which include Testicular Sperm Aspiration (TESA), Testicular Sperm Extraction (TESE), Percutaneous Epididymal Sperm Aspiration (PESA) or Microsurgical Epididymal Sperm Aspiration (MESA).
Previous studies show that mature sperm membranes possess a negative electrical charge between −16 mV to −20 mV, often termed zeta potential or electrokinetic potential. Further studies show different values of zeta potential for Y-bearing and X-bearing sperm being approximately −16 mV and approximately −20 mV, respectively (Ishijima S A et al., Int. J. Androl., 14 (1991), pp. 340-347). This difference in the electrical charge characteristics between the Y and X-bearing was utilized for selection of sperm according to morphology and kinematic parameters and was associated with increased fertilization and pregnancy after assisted reproduction procedures.
U.S. Patent Application, Publication No. 2013/0144357, discloses a device for increasing endogenous production of testosterone in a subject. The device includes a first electrode, a second electrode and a power source. The first electrode is configured to contact the skin in the pubic region of the subject. The power source is configured to deliver about 6 volts or corresponding to amperage between about 0.001 amps to about 0.003 amps.
There is an unmet need for advantageous techniques for improving male fertility and sperm reproductive capacity.